1. Technical Field
The present invention relates to a fan unit, an electronic apparatus including the fan unit, a method of opening/closing a shutter of the fan unit, and to the shutter, and more particularly to a fan unit including a shutter that can change an opening/closing direction according to an installation direction, an electronic apparatus including such fan unit, a method of opening/closing the shutter of the fan unit, and the shutter.
2. Related Art
Fan units have been used in various situations. For example, in electronic apparatuses such as a server or a disk array unit, the fan unit is employed for efficiently dissipating the heat generated in the apparatus. In various cases, the fan unit includes a shutter that blocks a reverse flow of air against the fan unit in case of a malfunction that causes the fan unit to stop. The electronic apparatus including a fan unit with a shutter can be found, for example, in JP-A No. H11-022698, JP-A No. 2005-011304, and JP-A No. 2006-059448.
[Patented document 1] JP-A No. H11-022698
[Patented document 2] JP-A No. 2005-011304
[Patented document 3] JP-A No. 2006-059448
The shutter of a conventional fan unit is set to close with its own weight because of the gravity, as described in the patented documents 1 and 2. Naturally, when the installation direction of the apparatus is changed (for example, vertical to horizontal), the shutter becomes unable to be closed. This permits air to reversely flow, thereby decreasing the amount of air introduced into the apparatus through the front side, which may lead to degraded cooling efficiency for the apparatus.
The patented document 3 discloses a fan unit including a mechanism that applies a force to the shutter from a hinge portion or the like, so as to cause the shutter to close the ventilation port. Such fan unit is, however, not yet free from the drawback that the shutter cannot be closed in the case where the apparatus is installed in a different direction. For example, when the gravity acts in a direction to open the shutter, the force urging the shutter to close may be overcome by the self weight of the shutter, thus leaving the shutter open. In this case, the force acting on the shutter from the hinge portion may be increased, so as to inhibit the shutter from remaining open even though the gravity acts in a direction to open the shutter. Increasing such force, however, in turn incurs the need to increase the force to open the shutter. For example, in the case where the mechanism utilizes the wind pressure of the fan to open the shutter, the shutter cannot be opened if the wind pressure is insufficient.
Accordingly, an object of the present invention is to provide a fan unit including a shutter capable of closing the shutter despite a change in installation direction of the fan unit, an electronic apparatus including such fan unit, and a method of opening/closing the fan unit.